In multipart/x-mixed-replace responses, `Content-Disposition: attachment` in the response header was not respected and did not force a download, which could allow XSS attacks. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.
https://www.mozilla.org/security/advisories/mfsa2024-59/
https://www.mozilla.org/security/advisories/mfsa2024-58/
https://www.mozilla.org/security/advisories/mfsa2024-56/